Delivering manganese from a lubricant source into a fuel combustion system

ABSTRACT

The present invention relates to an apparatus and method for delivering manganese from a lubricant source into a fuel combustion system or to the exhaust therefrom. By the present invention, manganese from the lubricant will interact with phosphorus, sulfur, and/or lead from the combustion products. In this manner, the manganese scavenges or inactivates harmful materials which have migrated into the fuel or combustion products, and which can otherwise poison catalytic converters, sensors and/or automotive on-board diagnostic devices. The present invention can also lead to improved durability of exhaust after treatment systems.

FIELD OF THE INVENTION

[0001] This application is a continuation of U.S. patent applicationSer. No. 10/313,310, filed on Dec. 6, 2002. That application isincorporated by reference herein in its entirety.

[0002] The present invention relates to an apparatus and method fordelivering manganese from a lubricant source into a fuel combustionsystem or to the exhaust therefrom. By the present invention, manganesefrom the lubricant will interact with phosphorus, sulfur, and/or leadfrom the combustion products. In this manner, the manganese scavenges orinactivates harmful materials which have migrated into the fuel orcombustion products, and which can otherwise poison catalyticconverters, sensors and/or automotive on-board diagnostic devices. Thepresent invention can also lead to improved durability of exhaust aftertreatment systems.

BACKGROUND OF THE INVENTION

[0003] A problem exists in fuel combustion systems in which the fuelcontains, or acquires, or produces upon combustion, one or more metal(e.g. lead), sulfur, and/or phosphorus contaminants that can poison ordegrade catalytic converters, sensors, or on-board diagnostic devices.

[0004] An additional problem is created by such contaminants in the formof undesirably increased levels of certain combustion products orby-products in the exhaust.

[0005] Yet another problem from such contaminants is a detrimentaleffect on after treatment systems. These contaminants can includeelemental phosphorus, lead and sulfur, or compounds thereof in the fuel,or in the air. The contaminants can also get into the fuel, or thecombustion chamber, or the combustion exhaust stream from the engine orcombustion system lubricants which often contain phosphorus-containingand sulfur-containing additives, and lead compounds associated withcombustion system wear.

[0006] It is a well-known phenomenon that vehicles and other combustionsystems consume, that is the engine burns, oil used as a lubricant forthe engine or moving parts of a combustion system. Various pathwaysexist for lubricating oil to enter the combustion system, and/or itsexhaust stream. Clearly the various components or additives in thelubricating oil also are consumed or burned and these components oradditives can have deleterious effects on the combustion system'scatalysts, after treatment system, and emissions.

[0007] It is therefore desirable to inhibit, reduce or prevent thedeleterious interaction of components (such as phosphorus, lead and/orsulfur arising from the lubricant source, air or fuel or otherwiseentering the combustion process) with the combustion exhaust stream tothereby prevent catalyst poisoning, after treatment system malfunction,and increased emissions.

SUMMARY OF THE INVENTION

[0008] In an embodiment, the present invention provides a method toinhibit, reduce or prevent the deleterious interaction of components(such as phosphorus, lead and/or sulfur arising from the lubricantsource, any processing aid or adjuvant, fuel, fuel additive, air orotherwise entering the combustion process) with the combustion exhauststream to thereby prevent catalyst poisoning, sensor poisoning, aftertreatment system malfunction, and/or increased emissions.

[0009] In another embodiment, the present invention provides a systemfor scavenging phosphorus, lead and/or sulfur from a fuel or theproducts resulting from the combustion of the fuel.

[0010] The present invention further relates to methods to improve thedurability of an after treatment device for a combustion system, whereinthe method includes contacting the products of the combustion of ahydrocarbonaceous fuel with a lubricant containing manganese in anamount sufficient for the manganese to interact with one or morecontaminants selected from the group consisting of phosphorus, sulfur,lead or compounds thereof in said products to thereby reduce the amountof one or more of the contaminants contacting the after treatmentdevice.

[0011] By “manganese” herein is meant any organomanganese compound ormaterial, including but not limited to methyl cyclopentadienyl manganesetricarbonyl, available as MMT® from Ethyl Corporation, manganesesulfonate, manganese phenate, manganese salicylate, alkylcyclopentadienyl manganese tricarbonyl, organic manganese tricarbonylderivatives, alkyl cyclopentadienyl manganese derivatives, neutral andoverbased manganese salicylates, neutral and overbased manganesephenates, neutral and overbased manganese sulfonates, manganesecarboxylates, and combinations and mixtures thereof. The manganese ispreferably present in the lubricant as an oil-soluble additive that canvolatilize and thereby enter the combustion chamber or exhaust stream.It may also enter the combustion chamber through “bulk” consumption,i.e., past valve guides or around piston rings. In one embodiment, thefuel or the exhaust from its combustion is treated with a low level ofmanganese, such as for example, a manganese level of about 20 ppm Mn inthe fuel or combustion exhaust or less.

[0012] By “base oil” herein is meant a base oil which can be selectedfrom the group consisting of paraffinic, naphthenic, aromatic,poly-alpha-olefins, synthetic esters, and polyol esters, and mixturesthereof. In a preferred embodiment, the base oil contains less than orequal to 0.03 wt. % sulfur, and greater than or equal to 90 wt. %saturates, and has a viscosity index greater than or equal to 80 andless than or equal to 120. In another embodiment, the base oil containsless than or equal to 0.03 wt. % sulfur, and greater than or equal to 90wt. % saturates, and has a viscosity index greater than or equal to 120.In a more preferred embodiment, the base oil is substantiallysulfur-free.

[0013] By “scavenging” herein is meant the contacting, combining with,reacting, incorporating, chemically bonding with or to, physicallybonding with or to, adhering to, agglomerating with, affixing,inactivating, rendering inert, consuming, alloying, gathering,cleansing, consuming, or any other way or means whereby a first materialmakes a second material unavailable or less available.

[0014] By “interaction”, “interacting” and “interacts” herein is meantscavenging.

[0015] By “inactivating” herein is meant scavenging.

[0016] By “hydrocarbonaceous fuel” herein is meant hydrocarbonaceousfuels such as but not limited to diesel fuel, jet fuel, alcohols,ethers, kerosene, low sulfur fuels, synthetic fuels, such asFischer-Tropsch fuels, liquid petroleum gas, fuels derived from coal,genetically engineered biofuels and crops and extracts therefrom,natural gas, propane, butane, unleaded motor and aviation gasolines, andso-called reformulated gasolines which typically contain bothhydrocarbons of the gasoline boiling range and fuel-soluble oxygenatedblending agents, such as alcohols, ethers and other suitableoxygen-containing organic compounds. Oxygenates suitable for use in thefuels of the present invention include methanol, ethanol, isopropanol,t-butanol, mixed alcohols, methyl tertiary butyl ether, tertiary amylmethyl ether, ethyl tertiary butyl ether and mixed ethers. Oxygenates,when used, will normally be present in the reformulated gasoline fuel inan amount below about 25% by volume, and preferably in an amount thatprovides an oxygen content in the overall fuel in the range of about 0.5to about 5 percent by volume. “Hydrocarbonaceous fuel” or “fuel” hereinshall also mean gasoline, bunker fuel, coal (dust or slurry), crude oil,refinery “bottoms” and by-products, crude oil extracts, hazardouswastes, yard trimmings and waste, wood chips and saw dust, agriculturalwaste, fodder, silage, plastics and other organic waste and/orby-products, and mixtures thereof, and emulsions, suspensions, anddispersions thereof in water, alcohol, or other carrier fluids. By“diesel fuel” herein is meant one or more fuels selected from the groupconsisting of diesel fuel, biodiesel, biodiesel-derived fuel, syntheticdiesel and mixtures thereof. It is preferred that the hydrocarbonaceousfuel is substantially sulfur-free, by which is meant a sulfur contentnot to exceed on average about 30 ppm of the fuel.

[0017] By “combustion system” and “apparatus” herein is meant, forexample and not by limitation herein, any diesel-electric hybridvehicle, a gasoline-electric hybrid vehicle, a two-stroke engine, anyand all burners or combustion units, including for example and withoutlimitation herein, stationary burners, waste incinerators, diesel fuelburners, diesel fuel engines, automotive diesel engines, gasoline fuelburners, gasoline fuel engines, power plant generators, and the like.The hydrocarbonaceous fuel combustion systems that may benefit from thepresent invention include all combustion units, systems, devices, and/orengines that burn fuels. By “combustion system” herein is also meant anyand all internal and external combustion devices, machines, engines,turbine engines, jet engines, boilers, incinerators, evaporativeburners, plasma burner systems, plasma arc, stationary burners, and thelike which can combust or in which can be combusted a hydrocarbonaceousfuel.

[0018] By “contacting” herein is meant the contacting, bringingtogether, reacting, complexing, coordinating, combining, admixing,mixing, and the like association between two or more materials, whetheror not a chemical or physical reaction or change occurs.

[0019] By “essentially free of phosphorus and compounds thereof” ismeant an amount of elemental phosphorus or a compound thereof which isless than about 10 ppm in the lubricant. Such low levels of phosphorusare desirable in many current lubricant formulations, and it isanticipated that lower levels of phosphorus in lubricants will becontinually sought, perhaps required. A preferred level of phosphorus inthe lubricant is an amount between 1 ppm and approximately 1500 ppm. Amore preferred level of phosphorus in the lubricant is an amount between500 ppm and 1200 ppm.

[0020] By “after treatment system” or “after treatment device” herein ismeant any system or device which contacts the combustion product(s) froma combustion chamber in a manner designed to oxidize, reduce orotherwise treat the combustion product(s). Examples, but not by way oflimitations herein, of such after treatment systems include anautomobile three-way catalytic converter, lean NO_(x) traps, catalyzeddiesel particulate filter and a continuously regenerating technologydiesel particulate filter. “After treatment system” also includesassociated sensors like O₂ sensors and NO_(x) sensors. Analogousgasoline combustion after treatment systems are known and are includedherein as deriving benefit from the present invention.

[0021] It is to be understood that both the foregoing generaldescription and the following detailed description are exemplary andexplanatory only and are intended to provide further explanation of thepresent invention, as claimed.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0022] In a more specific embodiment, the present invention provides amethod for reducing the amount of, or the deleterious effect from, atleast one contaminant selected from the group consisting of phosphorus,lead, sulfur, and compounds thereof in an exhaust stream from thecombustion of a hydrocarbonaceous fuel in a combustion system lubricatedby a lubricant, said method including the steps: (a) lubricating thecombustion system with the lubricant comprising a major amount of a baseoil of lubricating viscosity and a minor amount of one or more additivescomprising (i) at least one organosulfur compound, or at least oneorganophosphorus compound, or both, and (ii) at least one manganesesource; (b) combusting in the combustion system the hydrocarbonaceousfuel to produce combustion products comprising at least one materialselected from the group consisting of sulfur, lead, phosphorus, andcompounds thereof, and (c) contacting the manganese with the sulfur,lead, phosphorus, and compounds thereof in the combustion products,whereby the manganese interacts with the sulfur, lead, phosphorus,and/or compounds thereof. This interaction between the manganese and thesulfur, lead, phosphorus, and compounds thereof results in thescavenging of the contaminants, whereby several beneficial results areobtained. By scavenging the contaminants, the beneficial results includemaintaining catalytic converter performance, maintaining sensorperformance, maintaining LNT performance, and maintaining DPFperformance.

[0023] When cars are operated with manganese in the fuel, for examplewhen the gasoline has MMT® Fuel Additives added to it, its has beenshown that less phosphorus is deposited on the car's catalyticconverter. (See FIG. 1) The graph in FIG. 1 shows that less phosphorusis deposited throughout the catalyst when Mn has been combusted in thefuel. Specifically, FIG. 1 illustrates a greater than 50% reduction(from slightly less than 4 wgt % to about 1.5 wgt %) in the amount ofphosphorus on the catalyst when manganese is present in the exhaust.This is consistent with prior data showing Mn is combining in thecombustion or exhaust stream with phosphorus to form stablemanganese-phosphorus and manganese sulfate species that do not form.impermeable glazes on the catalyst. With less phosphorus on thecatalyst, less emissions “break through”, i.e., pass through asunconverted emissions. Therefore, it is desirable to have Mn in theexhaust stream.

[0024]FIG. 2 represents exhaust data showing percent emissions breakthrough of hydrocarbons, carbon monoxide, and NO_(x) based on Mn beingpresent or absent in the exhaust. With less phosphorus poisoning, thereis improved catalytic activity and lower levels of pollutants breakthrough the catalyst, leading to lower emissions. It is clear in FIG. 2that the undesirable emissions are significantly lower in the exhauststream coming from the combustion of fuel containing manganese.

[0025] The tests represented in FIG. 1 and FIG. 2 were 1993 Toyota Camryvehicles operated over 100,000 miles on either a base fuel or the basefuel plus 8.3 mg Mn/liter. After accumulating 100,000 miles, thecatalytic converters were dismantled and analyzed to determine theweight of phosphorus present at discrete points over their length. Thecatalysts were also analyzed to determine their efficiency, as measuredby the percent of emissions breaking through unconverted. The vehiclesoperated with Mn in the fuel (from MMT®) had less phosphorus depositedon the catalytic converter, resulting in less emissions breaking throughunconverted.

[0026] Further evidence of phosphorus protection and lower emissionsachieved by the presence of manganese in the combustion product of alubricant containing manganese can be drawn from a 1992/1993 EPA WaiverFleet test run by Ethyl Corporation, wherein cars burning gasolinecontaining Mn from the fuel additive MMT® at 8.3 mg Mn/liter producedlower CO and NOx emissions compared to cars burning a baseline fuelwithout the manganese source MMT®. (See FIG. 3, which utilized: 22vehicles (paired); 1993 Ford Escort TLEV, 1993 Toyota Camry, 1992 CrownVictoria, 1993 Honda Civic TLEV; vehicle selection based on AutomotiveCompany and EPA comments, Public Docket A-92 41, Nov. 9, 1992; mileageacc. fuel—300 ppm S—gasoline detergent used—MMT splash blended;emissions testing on all vehicles completed with the same certificationfuel.) The surface of the catalyst in the converter is not able todifferentiate the source of the manganese as being a fuel, or alubricant since these two material are simultaneously combusted farupstream from the catalyst.

[0027] In another test, the total suspended particulates (TSP) exhaustgas particulate emissions were collected from two separate Ford Taurusvehicles while operated over seven cycles of the EPA UniversalDynamometer Driving Sequence (UDDS). The filters were analyzed atLawrence Livermore National Labs using X-ray absorption spectroscopy(XAS) to determine the species of manganese present in the exhaust. Thedata in Table 1 shows the analysis results, wherein the predominantmanganese species are phosphates and sulfates, showing that themanganese is combining with phosphorus and sulfur which is derived fromthe engine lubricant and fuel. TABLE 1 Manganese Speciation by XAS (Wgt% of the exhaust perticulates) Vehicle Phosphates + Sulfates 1 84 2 82

[0028] The mass analysis in Table 1 has a 95% confidence limit of +/−5%.

[0029] It should be understood that the contaminants being scavengedaccording to the present invention by the manganese from the lubricantcan originate from the air utilized in the combustion of thehydrocarbonaceous fuel. In another embodiment, the contaminants beingscavenged according to the present invention by the manganese canoriginate from the hydrocarbonaceous fuel. In yet another embodiment ofthe present invention, the contaminants being scavenged by the manganesecan originate from the lubricant used to lubricate the combustionsystem.

[0030] In one embodiment, the lubricant-borne manganese which willscavenge the contaminant(s) can bleed, “blow-by”, flow, seep, be forcedor compressed, be drawn, sucked, or aspirated or otherwise accidentallyor deliberately get into a combustion chamber of the combustion system.In this embodiment, the contaminant(s) encounter and interact with themanganese during or after the combustion process, whereby scavengingoccurs. Thus an embodiment of a method of the present invention isachieved when lubricant containing manganese escapes around a valve inthe combustion system, such as for example and not as a limitationherein, an intake valve or an exhaust valve in an automotive engine. Inthis manner, the manganese is caused to encounter and interact with thecontaminant(s), whereby scavenging can occur.

[0031] In another embodiment, the manganese is caused, deliberately orinadvertently, to encounter the contaminant(s) in a passageway throughwhich the combustion products containing the contaminant(s) are conveyedaway from the combustion chamber. In this manner, the scavenging occursoutside the combustion chamber of the combustion system.

[0032] In another embodiment of the present invention, the manganesevolatilizes from the lubricant and is carried over into the combustionchamber containing the fuel.

[0033] In yet another embodiment, the combustion system utilizes adeliberate recirculating process, whereby vapors in a crankcase arerecirculated into either the intake manifold of the combustion chamber.In this manner, any lubricant containing the phosphorus, sulfur, and/orlead contaminants is caused to encounter and interact with manganese inthe combustion or exhaust.

[0034] Thus, in another test, a 1997 Ford Taurus was operated over sevencycles of the EPA UDDS. The fuel used during testing contained 8.3 mgMn/liter. The engine oil used in the crankcase had a phosphorusconcentration of 1000 ppm. The total mass of phosphorus and manganeseconsumed during the test were determined by mass-balance. TSP exhaustemissions were collected and analyzed to determine mass of manganese andphosphorus present on the filter. It was determined that the molar ratioof phosphorus to manganese on the TSP filters was equivalent to orcommensurate with the mass of those elements consumed through fuel andoil consumption. Table 2 illustrates the molar ratio of P:Mn consumed ascalculated and the mass collected on the filters. TABLE 2 VehicleOperation, Oil Consumption, Manganese Consumption and Molar Ratios Ratioof P:Mn Measured P:Mn on Filters 0.27 0.32

[0035] The present invention provides in another embodiment an apparatusfor performing a method for reducing the amount of, or deleteriouseffect of, at least one contaminant selected from the group consistingof phosphorus, lead, sulfur and compounds thereof in an exhaust stream,wherein the apparatus contains (a) a combustion chamber adapted tocombust a hydrocarbonaceous fuel; (b) a means to introduce thehydrocarbonaceous fuel into the combustion chamber; (c) a means toconvey combustion product from the combustion chamber; and (d) alubricant comprising a major amount of a base oil of lubricatingviscosity and a minor amount of one or more additives comprising (i) atleast one organosulfur compound, or at least one organophosphoruscompound, or both, and (ii) at least one manganese source. The apparatuscan further contain an after treatment device or system.

[0036] According to one embodiment of the present invention, theorganosulfur compound in the lubricant can be selected from the groupconsisting of sulfurized olefins, sulfurized fats and vegetable oils,sulfurized unsaturated esters and amides, ashless and metal containingdithiocarbamates, substituted thiadiazoles, sulfurized hindered phenols,sulfurized alkylphenols, neutral metal-containing sulfonate detergents,overbased metal-containing sulfonate detergents, neutralmetal-containing phenate detergents, and overbased metal-containingphenate detergents, or combinations and mixtures thereof.

[0037] According to another embodiment, the organophosphorus compound inthe lubricant can be selected from the group consisting of primary,secondary and aryl neutral and overbased zinc dialkyldithiophosphates(ZDDP's), trialkyl- and triarylphosphites, mixed alkyl/aryl phosphites,alkyl and aryl phosphorothiolthionates, and alkyl and arylphosphorothionates, and combinations or mixtures thereof.

[0038] It has been observed that a significant reduction in the amountof phosphorus detected on a device such as a catalyst can be achievedwhen manganese from methyl cyclopentadienyl manganese tricarbonyl is inthe exhaust stream from a combustion system. Specifically, reductions inthe amount of such contaminants above 20% by weight, and more preferablyreductions in an amount of from 60% to 80% by weight detected on theafter treatment device will be achieved by the present invention. Thisproduces a dramatic and highly desirable benefit in the improveddurability of such after treatment devices or systems.

[0039] The accompanying FIGS. 1, 2 and 3 further illustrate aspects ofthe present invention but do not limit the present invention.

[0040] Other embodiments of the present invention will be apparent tothose skilled in the art from consideration of the specification,Figures and practice of the invention disclosed herein. It is intendedthat the specification and Figures be considered as exemplary only, witha true scope and spirit of the invention being indicated by thefollowing claims.

What is claimed is:
 1. A lubricant for a combustion system other than atwo-stroke engine, the lubricant comprising a major amount of a base oilof lubricating viscosity and a minor amount of one or more additivescomprising at least one manganese source.
 2. A lubricant as described inclaim 1, wherein the one or more additives further comprises at leastone organosulfur compound.
 3. A lubricant as described in claim 1,wherein the one or more additives further comprises at least oneorganophosphorus compound.
 4. A lubricant as described in claim 2,wherein the one or more additives further comprises at least oneorganophosphorus compound.
 5. A lubricant as described in claim 1,wherein the combustion system is selected from the group consisting ofdiesel-electric hybrid vehicle, gasoline-electric hybrid vehicle,stationary burners, waste incinerators, diesel fuel burners, diesel fuelengines, automotive diesel engines, gasoline fuel burners, gasoline fuelengines, power plant generators, turbine engines, jet engines, boilers,incinerators, evaporative burners, plasma burner systems, and plasma arcsystems.
 6. A lubricant as described in claim 2, wherein theorganosulfur compound in the lubricant is selected from the groupconsisting of sulfurized olefins, sulfurized fats and vegetable oils,sulfurized unsaturated esters and amides, ashless and metal containingdithiocarbamates, substituted thiadiazoles, sulfurized hindered phenols,sulfurized alkylphenols, neutral metal-containing sulfonate detergents,overbased metal-containing sulfonate detergents, neutralmetal-containing phenate detergents, and overbased metal-containingphenate detergents, or combinations and mixtures thereof.
 7. A lubricantas described in claim 3, wherein the organophosphorus compound in thelubricant is selected from the group consisting of primary, secondaryand aryl neutral and overbased zinc dialkyldithiophosphates (ZDDP's),trialkyl- and triarylphosphites, mixed alkyl/aryl phosphites, alkyl andaryl phosphorothiolthionates, and alkyl and aryl phosphorothionates, andcombinations or mixtures thereof.
 8. A lubricant as described in claim1, wherein the manganese source in the lubricant is selected from thegroup consisting of methyl cyclopentadienyl manganese tricarbonyl, alkylcyclopentadienyl manganese tricarbonyl, organic manganese tricarbonylderivatives, alkyl cyclopentadienyl manganese derivatives, neutral andoverbased manganese salicylates, neutral and overbased manganesephenates, neutral and overbased manganese sulfonates, manganesecarboxylates, and combinations and mixtures thereof.
 9. A lubricant asdescribed in claim 1, wherein the manganese source in the lubricant ismethylcyclopentadienyl manganese tricarbonyl.
 10. A lubricant asdescribed in claim 1, wherein the base oil is selected from the groupconsisting of paraffinic, naphthenic, aromatic, poly-alpha-olefins,synthetic esters, and polyol esters, and mixtures thereof.
 11. Alubricant as described in claim 1, wherein the base oil contains lessthan or equal to 0.03 wt. % sulfur, and greater than or equal to 90 wt.% saturates, and has a viscosity index greater than or equal to
 120. 12.A lubricant as described in claim 1, wherein the base oil issubstantially sulfur-free.